What was found
DURING SCHEDULED INSPECTION, AILERON POWER CONTROL ACTUATOR PCA, FAILED AILERON ACTUATOR DAMPING COMPONENTS & MONITORING DEVICE FUNCTIONAL CHECK ON THE LT SIDE. REPLACED LT AILERON PCA, BUT IT WOULD NOT KEEP AILERON NEUTRAL WHEN HYD POWER WAS REMOVED. TROUBLE SHOT BY REPLACING LT AILERON PCA WITH THREE DIFFERENT REPAIRED UNITS, BUT NO CHANGE. CHECKED ACFT AILERON SYS & RIGGING, NO DEFECTS OR ANOMALY FOUND. CONTACTED TECHNICAL SUPPORT & THEY SAID THAT THE FIRST & SECOND PCA WERE BAD FROM THE STOCK, RECOMMENDED REPLACING THE MANIFOLD. REPLACED THE MANIFOLD, BUT NO CHANGE. AFTER THIRD PCA REPLACEMENT WITH NO CHANGE, REPLIED BACK TO US THAT AILERON PCA'S BYPASS VLVS MIGHT BE OPEN, CAUSING AILERON TO DROP WHEN HYD POWER WAS REMOVED, BUT IT WOULDN'T AFFECT NORMAL PCA OPERATION. OBTAINED A TECHNICAL DISPOSITION TO RETURN THE ACFT TO SERVICE, UNTIL NEW PCA IS DELIVERED.